Expansible reservoir unit for liquid cooled engines

ABSTRACT

An expansible coolant receiving reservoir receives the entire expanded volume of coolant in a liquid cooled system to provide for an air-free coolant system. A slightly increased pressure is applied to the coolant up through normal operating temperatures, and a substantially greater pressure at higher temperatures, both pressures being lower than the pressure radiator cap setting.

United States Patent [191 Birdwell, Sr.

[4 1 Oct. 16, 1973 EXPANSIBLE RESERVOIR UNIT FOR LIQUID COOLED ENGINES [76] Inventor: Venson E. Birdwell, Sr., Rt. 10, Box

245, Athens, Ala. 35611 [22] Filed: Oct. 8, 1971 [21] Appl. No.: 187,701

Related US. Application Data [63] Continuation-in-part of Ser. No. 842,936, July 18,

1969, abandoned.

[52] US. Cl 123/41.5, 123/4l.5'l, 123/41.54 [51] Int. Cl. F0lp 11.02 [58] Field of Search 123/41.22, 41.27,

[56] References Cited UNITED STATES PATENTS 3,168,080 2/1965 Latterner 123/4l.5

3/1966 Simpson 123/4l.5

2,436,281 2/1948 Bartlett et al.... 123/41.51

2,086,441 7/1937 Rushmore l23/41.54 2,878,794 3/1959 Stromberg 123/4l.5

FOREIGN PATENTS OR APPLICATIONS 964,429 12/1960 Great Britain l23/4l.5

Primary Examiner-Laurence M. Goodridge Assistant Examiner-Cort R. Flint AttorneyEdward Shlesinger, Jr. et a1.

57 ABSTRACT An expansible coolant receiving reservoir receives the entire expanded volume of coolant in a liquid cooled system to provide for an air-free coolant system. A slightly increased pressure is applied to the coolant up through normal operating temperatures, and a substantially greater pressure at higher temperatures, both pressures being lower than the pressure radiator cap setting.

11 Claims, 5 Drawing Figures EXPANSIBLE RESERVOIR UNIT FOR LIQUID COOLED ENGINES This application is a continuation-in-part of U.S. Pat. application Ser. No. 842,936, filed July 18, 1969 now abandoned.

BACKGROUND OF INVENTION In liquid cooled engines, particularly automotive vehicles, pressurized liquid coolant systems have been in use for many years. These pressurized systems permit the coolant to operate at higher temperatures without boiling, but do have several drawbacks. Due to expansion of the coolant at high temperatures there is frequently loss of coolant through the pressure relief in the radiator cap.

This condition is prevelent in warm weather for automotive engines, where the coolant temperature is high due to the high ambient temperature, and air conditioners or sustained high running speeds place an additional burden on the engine itself, increasing operating temperatures. The temperature of the coolant rises to a high level and the additional expanded volume is discharged through the pressure relief valve in the radiator cap, particularly after the engine is stopped or slowed down. Repeated loss of small amounts of coolant reduces substantially the cooling capacity of the system. This can eventually bring about a boil-over condition, with loss of most of the coolant of the system and possible damage to the engine or auxiliary equipment.

This situation is very common in warm weather when stop-and-go traffic is encountered.

The ordinary pressurized system also requires that a definite air space of approximately two to three inches be left at the top of the radiator to allow for expansion of the coolant under operating conditions. In the course of operation the air is entrained in the circulating coolant, resulting in oxidation of the surfaces in-the cooling system.

This invention relates to a device for overcoming the abovementioned drawbacks of conventional pressurized systems and more particularly to a specific coolant accumulator assembly which is readily attached to and functions as part of a conventional pressurized liquid cooling system for engines.

It permits expansion of the liquid coolant under controlled pressure conditions as part of a completely airsealed system in which the air space at the top of the radiator of the conventional presurized system is eliminated.

The device permits the slow pressurization of the sys tem under low pressure at normal operating temperature levels of the coolant, and permits substantially greater pressureto be applied to the coolant when above normal operating temperatures are encountered.

The device prevents loss of coolant from the system due to spill-over, gives an increased radiator capacity, makes possible operation of the cooling system under reduced pressures, provides a sealed system, controls oxidation in the cooling system, and all but eliminates the overheating problem of conventional pressurized coolant systems.

These and further advantages of the subject invention will become apparentfrom the drawings and description.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows the device of the subject invention and a water pressure gauge connected to the radiator of a typical pressurized cooling system for automobile engines.

FIG. 2 is a top view of the device of the subject invention.

FIG. 3 is a cross-sectional view of the unit along lines 3-3 of FIG. 2.

FIG. 4 is a partial view of the unit of FIG. 3 in unexpanded contracted position.

FIG. 5 is a cross-sectional view of a second modification of the invention.

DESCRIPTION OF THE INVENTION Referring particularly to FIG. 1, a conventional pressurized radiator assembly having a radiator 12 and a pressurized cap 14 with a spring valve assembly is completely filled with liquid coolant.

The petcock drain conduit 18 has a yieldable expansion container assembly 20 connected thereto by a conventional tube, not shown, a part of the petcock valve.

The expandable reservoir unit 20 has a bellows 22 connected to the petcock equipment 18 through the liquid supply line 24. A bleed valve 26 at the top of the bellows unit 22 is connected through a line 28 and fitting 30 to the overflow chamber of the radiator.

A water gauge 32 is connected through line 34 and tee 36.

The bellows unit 22 is precompressed by springs 38 and 40 shown in FIG. 1. A third spring 42 is shown in FIG. 2 and it can be seen that the springs are positioned equidistant about the periphery of the bellows container 22. The bellows has a sealed top plate 44. Spring support brackets 46, 48 and 50 hold the top ends of springs 38, 40 and 42 in position. The entire reservoir unit 20 is supported by means of the mounting flanges 52 and 54 shown in FIGS. 2 and 3.

The detailed construction of the expansion reservoir unit 20 is shown in FIG. 3. The corrugated bellows wall 56 forms the outer shell of the assembly, and an inner cylindrical wall 58 extending upwardly and spaced a short distance therefrom forms the inner wall. The inner wall has a circular top piece 60 in sealing engagement therewith and is welded or otherwise connected through the lower edge 62 of the bellows 56.

A coolant supply fitting 64 passes through the inner wall 58 to the annular sealed space 66 between the corrugated bellows wall 56 and the inner wall58. Its lower end is connected'to the forward supply hose 24 connected to the petcock 18 of the radiator.

As the coolant expands under operating conditions the expanded volume is supplied through line 24 and fittings 64 to the annular space 66, and as the pressure increases the bellows is pressed upwardly away from the inner top wall 60 creating the expansion chamber area '68 in which the expanded volume of coolant is received. The size of this chamber will vary with expansion of the fluid, and can accommodate the entire expanded volume of coolant. The amount of pressure exerted by the springs is determined by the spring rate and by the adjustable tensioning bolt and nut assembly 70, which is identical for all three springs. The lower end of the spring is connected to a lower spring support bracket 72 by a hook 74. All three spring assembly constructions and their support arrangements are identical.

In FIG. 4, the partial section of the bellows assembly is shown when the expansion reservoir unit is in its contracted state with the upper and lower walls of the expansible cavity 44 and 60 very close together. In this position the bellows is precompressed by the spring assembly so that the force exerted by the bellows wall in the initial state is upwardly and outwardly against the compression of the springs 38, 40 and 42. In the preferred embodiment the bellows is approximately 6 inches in diameter and 8 inches long in its noncompressed state. The springs compress it downwardly to a length of approximately 6 inches. The outward force of the bellows wall is approximately 33 pounds, while the compression force of the three springs is approximately 45 pounds. The relative dimensions of the bellows assembly members are chosen so that the free length of the bellows is reached when the coolant in the entire system reaches the high limit of the normal operating temperatures for the engine. Referring to FIG. 3, the expansion chamber 68 would increase to the volume indicated by the arrow 76, which would coincide with the free length non-contracted length of the bellows wall 56. During this entire period the bellows wall would be pressing outwardly against the force of the springs 38, 40, and 42, and the coolant expanding into the chamber would be subjected to the small differential pressure between the springs and bellows.

Once the coolant expands beyond the point indicated by arrow 76 and into the upper area 78, the force of the bellows 56 changes from an outward push to an inward pull and in this instance both the bellows spring force and the springs force cooperate to exert a downward force on the fluid in the expanded chamber area 68 to a very high pressure. In the preferred embodiment the pressure subjected to the fluid in the range indicated by the arrow 76 is approximately 2 to 3 pounds per square inch, while in the area indicated by the arrow 78 the force is approximately 10 and 12 pounds per square inch. It will be noted that both of these pressures are below the normal release pressure for the relief spring and valve assemblies setting of approximately 15 pounds per square inch of the radiator cap.

The capacity of the assembly to the normal driving temperature limit is approximately 1 quart of coolant. In the preferred embodiment stainless steel has been used for the bellows wall, although brass and bronze are also excellent materials for such use. Welding is used to seal the inner wall 58 to the bellows 56, as well as to add the top plate 60 to the inner wall 58. The reservoir top 44 is also welded to the bellows, as are the spring and brackets, the mounting flanges and the fluid' through the plate 88 and is welded at 96 thereto. It ex--. tends the full length of the bellows assembly, and is in fluid communication with the annular chamber 98 between the inner and outer bellows walls. The lower portion of the spring housing 84 is formed by the lower spring casing cylinder 100, into which the lower end of the upper bellows spring casing 94 is telescopically received. Upper and lower brackets 102 and 104 within the cylindrical telescoping members support compression spring 106. Spring 106 acts in the same fashion as springs 38, 40, and 42 of FIGS. 1 through 4, precompressing the two bellows walls 86 and 90, so that their action opposes the'force of the spring until they are stretched below their free length.

The bleed valve 108, acts in the same fashion as bleed valve 26. Bleed line 110 corresponds to line 28 of FIG. 1. The valve is left open during filling until coolant is observed running through the line, at which time the valve is closed.

Arrows 112 indicate the expansion range of the outer bellows while arrows 114 indicate the contraction range of the inner bellows. As the operating temperature increases and the fluid coolant flows through the fitting 92 the main reservoir receiving chamber 16 is enlarged to accommodate the entire expanded volume of coolant. In this unit, the outer bellows 86 and the inner bellows exert forces in the opposite direction. As the reservoir is filled, the outer bellows expands, while the inner bellows contracts.

OPERATION The unit may be used in connection with any type of liquid cooled vehicle. However, its most widespread application is in the automotive field, where all the heating of the conventional pressurized liquid cooled system for automobile engines is a persistent problem.

The bellows unit is mounted under the hood of the automobile adjacent the radiator, 12, as shown in FIG. 1, by the mounting brackets 52 and 54, and the fluid supply line 24 is connected behind the petcock valve The unit in place is adjusted so that it is precompressed bythe springs 38, 40, and 42 so that the bellows on being compressed will reduce the volume of the chamber 68 by an amount equal to the volume of the expanded volume of coolant under the normal operating temperature.

,In this modification the outer bellows wall 56, which has an outer diameter of 6 inches and an inner diameter of 5 inches, the wall thickness being five thousandths of an inch. lts spring rate is slightly more than 12 pounds per inch. Under normal driving conditions the reservoir 68 will accommodate slightly over a quart of coolant liquid. This will vary with the total capacity of the cooling system.

The unit in operation will prevent boiling of coolant up through 260 F if the cooler used is water. The unit should be able to accommodate slightly more than 12 percent of the total cooling system fluid capacity.

The water pressure gauge 32 is connected to the dashboard of the automobile in view of the operator. A sharp increase in pressure willindicate that the operating temperature of the coolant is high and above the normal operating range.

It should be noted that as soon as the volume of coolant exceeds the normal amount of expansion the be]- lows unit places high pressure on the coolant to inhibit boiling. The entire amount of coolant, both upstream and downstream of the water pump is pressurized with this arrangement. However, should excessive pressures develop, the radiator relief valve 16 will open at 15 pounds per square inch.

The central spring-type unit shown in FIG. 5 is installed and operated in the same manner as the unit of FIGS. 1 through 3. With this unit, the internal annular wall 90 is a bellows which has a spring rate less than that of the exterior wall and cooperates in exerting force in the same direction against single central spring 106. The outer bellows 86 has a spring rate of 14 pounds per inch in the normal operating range, while the interior annular bellows 90 has a spring rate of II pounds per inch.

With this assembly there is automatic pressure regulation of the entire body of coolant in the engine system, prevention of loss of coolant, increased capacity of the coolant system through elimination of the normal air space in the radiator, no oxidation because of the elimination of entrained air in the coolant liquid, and less pressure applied to the entire coolant system under normal operating conditions.

While this invention has been described, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses and/or adaptations ofthe invention following in general the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as may be applied to the essential features hereinbefore set forth, as fall within the scope of the invention or the limits of the appended claims.

What I claim is:

1. In an engine having a pressurized liquid cooling system, an automatic pressure compensating unit, comprising:

a. a closed expansible volume means having a direct fluid connection to the engine cooling system for receiving the entire expanded volume of coolant when it expands due to engine operation,

b. the expansible means having fill means for permitting filling of the entire volume of the expansible volume means to eliminate all air pockets from the system,

c. yieldable contracting means associated with the expansible volume means for permitting it to accommodate the increased coolant volume,

d. the contracting means including a low pressure compressing means for applying a small pressure on the expansible volume means through normal engine coolant operating temperatures, and

e. the contracting means also including a high pressure compressing means for automatically applying a second and substantially greater pressure on the expansible volume means when higher than normal engine coolant operating temperatures are reached.

2. In an engine having a pressurized liquid cooling system, an automatic pressure compensating unit as set forth in claim 1, wherein:

a. the closed expansible volume means is a bellows,

b. the yieldable contracting means includes a spring assembly which is connected to and precompresses the bellows to a point where the bellows is contracted until a volume greater than the expansion volume of the coolant at normal operating temperatures is received therein.

3. In an engine having a pressurized liquid cooling system, the automatic pressure compensating unit as set forth in claim 2, wherein:

a. the bellows has an interior closed cylindrical member in sealing engagement therewith to form the inner wall of the closed expansible volume means, and

5 b. the bellows has a top plate at the other end thereof, the expansible volume for receiving the expanded coolant being disposed between the closed end of the interior cylinder, the expanded section of bellows, and the top plate.

4. In an engine having a pressurized liquid cooling system, the automatic pressure compensating unit as set forth in claim 3, wherein:

a. the closed expansible volume means is directly connected to the radiator of the liquid coolant system.

5. In an engine having a pressurized liquid cooling system, the automatic pressure compensating unit as set forth in claim 1, wherein:

a. the closed expansible volume means includes. two

concentric annularly spaced bellows members connected in sealing engagement at their lower end,

b. the yieldable contracting means includes an elongated spring assembly disposed within the two bellows members and connected at one end to the exterior bellows member and at the other end to the interior bellows member.

6. An expansible coolant receiving assembly for the expanded volume of coolant from the cooling system of an engine, comprising:

a. a container having concentric inner and outer parallel walls disposed in close proximity with respect to each other defining therebetween a thin annular chamber,

b. each of the walls having an end member at the same end, the end members disposed adjacent to each other, and defining a coolant receiving chamber therebetween which is in communication with the thin chamber between the inner and outer walls,

c. bleed valve means connected to one of the walls and in communication with the coolant receiving chamber,

d. one of the walls having an axial section which is expandable,

e. mechanical means for exerting force on the walls for maintaining a slight pressure on expanded coolant received within the chamber, and

f. conduit means connected through one of the walls for supplying expanded coolant from the cooling system of the engine.

7. The expansible coolant receiving assembly as set forth in claim 6, wherein one of the walls is a bellows member. 8. The expansible coolant receiving assembly as set forth in claim 6, wherein:

a. the mechanical means for exerting force on the walls is a compression spring assembly.

9. The expansible coolant receiving assembly as set forth in claim 7, wherein:

a. both the inner and the outer wall are bellows members.

10. The expansible coolant receiving assembly of 60 claim 7, wherein:

a. mechanical means for exerting force on the walls comprises an adjustable compression spring assembly.

11. The expansible coolant receiving assembly as set 65 forth in claim 9, wherein:

a. the mechanical means for exerting force on the walls is a central compression spring assembly. 

1. In an engine having a pressurized liquid cooling system, an automatic pressure compensating unit, comprising: a. a closed expansible volume means having a direct fluid connection to the engine cooling system for receiving the entire expanded volume of cooLant when it expands due to engine operation, b. the expansible means having fill means for permitting filling of the entire volume of the expansible volume means to eliminate all air pockets from the system, c. yieldable contracting means associated with the expansible volume means for permitting it to accommodate the increased coolant volume, d. the contracting means including a low pressure compressing means for applying a small pressure on the expansible volume means through normal engine coolant operating temperatures, and e. the contracting means also including a high pressure compressing means for automatically applying a second and substantially greater pressure on the expansible volume means when higher than normal engine coolant operating temperatures are reached.
 2. In an engine having a pressurized liquid cooling system, an automatic pressure compensating unit as set forth in claim 1, wherein: a. the closed expansible volume means is a bellows, b. the yieldable contracting means includes a spring assembly which is connected to and pre-compresses the bellows to a point where the bellows is contracted until a volume greater than the expansion volume of the coolant at normal operating temperatures is received therein.
 3. In an engine having a pressurized liquid cooling system, the automatic pressure compensating unit as set forth in claim 2, wherein: a. the bellows has an interior closed cylindrical member in sealing engagement therewith to form the inner wall of the closed expansible volume means, and b. the bellows has a top plate at the other end thereof, the expansible volume for receiving the expanded coolant being disposed between the closed end of the interior cylinder, the expanded section of bellows, and the top plate.
 4. In an engine having a pressurized liquid cooling system, the automatic pressure compensating unit as set forth in claim 3, wherein: a. the closed expansible volume means is directly connected to the radiator of the liquid coolant system.
 5. In an engine having a pressurized liquid cooling system, the automatic pressure compensating unit as set forth in claim 1, wherein: a. the closed expansible volume means includes two concentric annularly spaced bellows members connected in sealing engagement at their lower end, b. the yieldable contracting means includes an elongated spring assembly disposed within the two bellows members and connected at one end to the exterior bellows member and at the other end to the interior bellows member.
 6. An expansible coolant receiving assembly for the expanded volume of coolant from the cooling system of an engine, comprising: a. a container having concentric inner and outer parallel walls disposed in close proximity with respect to each other defining therebetween a thin annular chamber, b. each of the walls having an end member at the same end, the end members disposed adjacent to each other, and defining a coolant receiving chamber therebetween which is in communication with the thin chamber between the inner and outer walls, c. bleed valve means connected to one of the walls and in communication with the coolant receiving chamber, d. one of the walls having an axial section which is expandable, e. mechanical means for exerting force on the walls for maintaining a slight pressure on expanded coolant received within the chamber, and f. conduit means connected through one of the walls for supplying expanded coolant from the cooling system of the engine.
 7. The expansible coolant receiving assembly as set forth in claim 6, wherein one of the walls is a bellows member.
 8. The expansible coolant receiving assembly as set forth in claim 6, wherein: a. the mechanical means for exerting force on the walls is a compression spring assembly.
 9. The expansible coolant receiving assembly as set forth in claim 7, wherein: a. both the inner and the outer wall are bellows members.
 10. The expansible cOolant receiving assembly of claim 7, wherein: a. mechanical means for exerting force on the walls comprises an adjustable compression spring assembly.
 11. The expansible coolant receiving assembly as set forth in claim 9, wherein: a. the mechanical means for exerting force on the walls is a central compression spring assembly. 